This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This study will examine how insulin and glucose levels relate to how rapidly the brain ages. High levels of glucose and insulin may accelerate brain aging and appear to increase one's risk of Alzheimer's disease. This study will also examine how body metabolism relates to how rapidly the brain ages.